Hawaii

Hawaii Permit Guide for Metal Carports, Garages and Barns

In Hawaii, plan on a county building permit for a metal carport or garage, because the permit comes from your county building office and the state code sets no statewide exemption for them. Hawaii has five counties on paper, but building permits are run by four county governments: the City and County of Honolulu, Hawaii County, Maui County and Kauai County. All four build from the same Hawaii State Building Codes, which are based on the 2018 International Building Code and International Residential Code with Hawaii amendments. The state version drops most of the permit and administration chapter, so each county's own ordinance decides what work is exempt and what needs plans. Wind is the big structural issue on every island, and the state amendments carry their own hurricane wind speeds and county topographic maps. If you are researching a Hawaii carport permit, start with your county building office and ask about wind design, setbacks and zoning before you order.

Building code in effect

The Hawaii State Building Code Council, attached to the Department of Accounting and General Services (DAGS), adopts the statewide codes under HRS 107-24 and 107-25. The council's current list shows the 2018 International Building Code, 2018 International Residential Code, 2018 IECC, 2018 IEBC, 2018 Uniform Plumbing Code and 2018 NFPA 70, each with Hawaii amendments. The state building code document states an effective date of April 20, 2021. Under HRS 107-28, each county must adopt and may amend the state codes within two years of state adoption, and if a county misses that deadline the state codes apply as an interim county code. The council's page notes that the Governor's emergency proclamation on housing (15th proclamation, September 23, 2025) suspends that two-year default deadline, though counties can still update their own codes. As an example of local adoption, Honolulu's Department of Planning and Permitting lists the 2018 IBC and 2018 IRC in effect from August 9, 2024.

Who issues permits

Building permits in Hawaii are issued by the counties, not by the state. The State Building Code Council writes the base code, but the Hawaii amendments delete most of Chapter 1 (administration) of the IBC, so permit triggers, exemptions, fees and inspections come from each county's ordinance. On Oahu, the City and County of Honolulu Department of Planning and Permitting handles building permits, and its site says permits are required under ROH 18-3.1. On the Big Island, Maui County (Maui, Molokai and Lanai) and Kauai, the county building office handles the same job under its own building code ordinance. Zoning, setbacks and lot coverage are also set by the county, so a building can pass structurally and still need zoning sign-off.

County permit guides

Don't see your county? Call 919-725-8176 and we'll help you find the right office.

When you need a permit

Garages and enclosed buildings: An enclosed metal garage or workshop is treated as a building under the county's adopted 2018 IBC or IRC, so expect a building permit with plans that show the wind design and anchoring.
Carports and open covers: A carport is still a roofed structure that has to resist Hawaii's design wind speeds, and the state code sets no blanket exemption for it. Ask your county building office whether your size and location need a permit.
Small sheds: Small-shed exemptions, if any, come from county ordinance because the state code deletes the IBC permit chapter. Get the county's exempt-work list in writing before skipping a permit.
Electrical and plumbing: Lights, outlets or plumbing in a garage need separate county permits and licensed installers, even for agricultural buildings that are otherwise exempt under HRS 46-88.
Flood zones and coastal lots: Any work in a mapped flood zone is checked against National Flood Insurance Program rules, and HRS 46-88 says even exempt farm buildings must clear that review first.

Farm buildings

Hawaii has a specific farm building exemption in HRS 46-88. Nonresidential agricultural buildings of no more than 1,000 square feet, including one-story wood-frame or masonry farm buildings with a structural span under 25 feet, can be exempt from building permits and building code requirements, and buildings from 1,000 to 8,000 square feet can be exempt if they meet the building code or a county, national or international prescriptive standard. The building has to be on a commercial farm or ranch on land used mainly for agriculture, with at least two contiguous acres, and the total exempt floor area per zoning lot is capped (5,000 square feet on lots of two acres or less). You must give the county written notice of the size, type and location first, wait for the county to confirm no floodplain permit is needed (it has 30 days to certify), and file an as-built notice within 30 days of finishing. The exemption does not apply in the state land use urban district, buildings must be at least 15 feet apart, and electrical or plumbing hookups still need county permits.

Wind and snow

Hawaii does not deal with snow loads, but hurricane wind is the main design load on every island. The state amendments to the 2018 IBC set ultimate design wind speeds of 130 mph for typical Risk Category II buildings and 115 mph for Risk Category I, before topographic effects. They also include county-by-county topographic factor maps and exposure maps for Hawaii, Maui, Molokai and Lanai, Oahu and Kauai, because ridges and valleys can raise wind speeds well above the base number. Areas where the design wind speed is 130 mph or more are treated as windborne debris regions. Ask your county what wind speed and exposure apply to your exact lot before you order, since a hillside or coastal site can need a higher rating than the base speed. Our partnered manufacturers offer certified buildings rated for 140 MPH wind and 35 PSF snow load, and higher ratings can be quoted where required.

Before you order

Call your county building office and ask for the design wind speed, topographic factor and exposure category for your lot.
Confirm your zoning district, setbacks and lot coverage with the county, since zoning is separate from the building code review.
If you plan to use the HRS 46-88 farm exemption, file the written notice with the county and wait for its floodplain answer before any work starts.
Check the flood zone for your parcel, especially on coastal or low-lying lots, and plan separate permits for any wiring or plumbing.

Common questions

Do I need a permit for a carport in Hawaii?
Usually you should expect one. Permits come from the county, the state code does not exempt carports, and every carport has to be designed for Hawaii's wind loads. Your county building office can tell you if a small cover is on its exempt list.

Do I need a permit for a metal garage in Hawaii?
Yes, in most cases. An enclosed metal garage is a building under the county's adopted 2018 IBC or IRC, so plan on a building permit with wind design and foundation details, plus separate permits for any electrical or plumbing.

Are farm buildings exempt in Hawaii?
Some are. HRS 46-88 exempts nonresidential agricultural buildings up to 1,000 square feet, and up to 8,000 square feet if they meet a prescriptive standard, on commercial farms or ranches of at least two acres outside the urban district. You still have to notify the county in writing first and get its floodplain answer.

Which building code edition does Hawaii use?
The State Building Code Council's current list shows the 2018 IBC and 2018 IRC with Hawaii amendments. Counties adopt and amend these codes under HRS 107-28, so check your county's current local amendments too.

Sources

Permit rules change. Always confirm with your local permit office before you build.

Looking at buildings? See our metal carports, metal garages and metal buildings.

Ready to design your building?

Design it yourself in 3D with the button below, or call 919-725-8176 and we'll help you figure out what your county needs.

Design Your Building in 3D